OAKLAND -- Already reeling from two nights of vandalism and violence, Oakland was mopping up Tuesday morning after a third night of protests downtown that left more smashed windows and storefronts, graffiti and scattered debris from demonstrators' clashes with police.

The crowd of several hundred were protesting Saturday's acquittal of George Zimmerman in Florida and briefly shut down traffic on Interstate 880 and blocked several streets.

During the protesters' marches and skirmishes with police downtown, more than a dozen businesses were vandalized, including some targeted during previous protests. City cleanup crews started at 6 a.m. "to get a head start" on the garbage and other debris, one worker said.

Workers finish boarding up the large hole created by a shattered window at the Men's Wearhouse on Telegraph in Oakland, Calif. on Tuesday, July 16, 2013 after another night of protest and vandalism in downtown Oakland. A large group of protestors marched for Trayvon Martin after the not guilty verdict for George Zimmerman was announced Saturday. (Laura A. Oda/Bay Area News Group)
(Laura A. Oda)

Among those targeted for the first time were Comerica Bank, 1200 Broadway, the Burger King restaurant at 13th and Broadway, Youth Radio, 1701 Broadway, and Men's Wearhouse, 300 Frank H. Ogawa Plaza. All had windows smashed.

Those vandalized previously that were damaged again Monday night and early Tuesday included Sears Roebuck and Co., 1950 Broadway, which had additional windows smashed and paint splattered, and the restaurant Flora, 1900 Telegraph Ave., where a waiter was savagely attacked and windows were broken.

Already boarded-up windows on some businesses became easels for graffiti, including the Oakland Tribune offices at 1900 Broadway, T-Mobile at 13th and Broadway, Foot Locker in the 1400 block of Broadway and the California Bank and Trust at 19th and Franklin streets.

Business owners and others were concerned over the damage and were worried about when it would end.

Al Golshami, manager of El Senor Burrito 3 at 430 13th St., said he was glad that no damage was done to his business, which had boarded up its windows in advance. He said he plans to keep them boarded up "for the next few days."

A security guard working his first day at the MASH building, 428 13th St., said he had not been told how long he would be there.

Ratha Kuch, 41, owner of the Buongiorno restaurant on Broadway, which just recently opened, felt fortunate that none of his windows were broken and had no plans to board them up. "I'm frustrated and I hope this ends soon," he said.

During the night's protests, a restaurant worker at Flora in Oakland's Uptown area was injured when he was hit by a masked, hammer-wielding attacker.

Another injury was reported by witnesses who said a protester was injured and writhing in pain at Broadway and 16th Street after apparently being struck in the shoulder by a police projectile. Police are still investigating whether anyone was hit by an object, whether it came from police or from the crowd. Police have not been able to locate the person who was injured. At one point, a squad of officers making arrests of vandalism suspects was surrounded by protesters throwing rocks and bottles and they responded by firing one tear-gas round, police said.

The nine arrests made by police Tuesday night included suspicion of assault with a deadly weapon, resisting arrest, vandalism and similar offenses. One replica firearm (BB gun) was recovered from a protester.

Oakland developer Phil Tagami said he watched vandals deface one of his own buildings last night.

"Oakland is a very progressive town and we're very understanding of different points of view and we'll continue to defend people's rights to peacefully assemble and protest. That's part of the DNA of Oakland," he said. "What we don't appreciate is the lawlessness and the anarchy and the physical violence as well as the property damage.

"I saw the crowd out there last night. When people are smashing out the windows of Youth Radio that's clearly someone who isn't from Oakland or even about what the issue is. They're anarchists. These are local businesses with local owners with local employees. These are not chained businesses. I don't get it. That's the disconnect."

Tagami, who in 2011 provided a one-man sentry for the Rotunda Building in Frank H. Ogawa Plaza that he oversaw a $50 million renovation on in years past, called for a zero-tolerance policy regarding the vandalism.

"If you're doing that you're going to jail. If you're hitting someone with a hammer you're going to jail," he said. "That person has to be found and held to account."